There are image sensors known in the related art that include focus detection pixels disposed in a cross-shaped pattern in correspondence to a focus detection area set on the photographic field, so as to detect the focusing condition of an optical system along two directions assumed on the photographic filed (see, for instance, patent reference literature 1).
The prior art literatures related to the present invention include the following.
Patent reference literature 1: Japanese Laid Open Patent Publication No. 2000-292686